The rotax max engines are very expensive and cost a lot to rebuild, plus they are direct drive, im going to go with a bike engine as parts a cheaper and im not restricted in what I can do.
With regards to grip, I will be getting the 210mm rears and some decent Dunlop rubber used for the higher power karts. The superkarts get plenty of grip and they are around 90bhp. So I think thats my max power I can go for as any more power it might be an issue with traction.
I was looking at single cylinder engines, but now I have been told I won\'t be allowed on kart tracks I am thinking of upgrading that idea. The inline 4 engines are too wide to fit on the kart in the OEM engine position - well they do fit, but they are unstable and so they have to be mounted behind the driver.
I then got thinking about what other engines might fit and I then came across a possible answer - V twin engines - I don\'t need to worry about how long the engine is, just the width.
I have found the VFR400, VFR600 and VFR1000 engines, need to get specs on the width etc, but I found a complete VFR400 project bike for £250! the engine has around about 60bhp as stock, I will have a look around closer to the time though, still getting ideas, but I think a v twin engine might work. The issue I am coming up with regarding 2 strokes is there aren;t many large capacity single cylinder engines anymore, so it might be easy to go multi cylinder.